Re: [PATCH] cxgbit: fix dma_addr_t printk format

[Joe Perches]

On Sat, 2016-03-05 at 01:04 +0100, Arnd Bergmann wrote:
> The newly added driver prints a dma_addr_t using the %llx format string,
> but that is wrong on most 32-bit architectures:
> 
> drivers/target/iscsi/cxgbit/cxgbit_ddp.c: In function 'cxgbit_dump_sgl':
> drivers/target/iscsi/cxgbit/cxgbit_ddp.c:180:10: error: format '%llx' expects argument of type 'long long unsigned int', but argument 8 has type 'dma_addr_t {aka unsigned int}' [-Werror=format=]
>    pr_info("\t%d/%u, 0x%p: len %u, off %u, pg 0x%p, dma 0x%llx, %u\n",
> 
> Unfortunately, we can't use the %pad format string here because
> we are not printing an lvalue, so we have to add a cast to u64, which
> matches the format string on all architectures.
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> Fixes: c49aa56e556d ("cxgbit: add cxgbit_ddp.c")
> ---
>  drivers/target/iscsi/cxgbit/cxgbit_ddp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/target/iscsi/cxgbit/cxgbit_ddp.c b/drivers/target/iscsi/cxgbit/cxgbit_ddp.c
> index 07e2bc86d0df..d667bc88e21d 100644
> --- a/drivers/target/iscsi/cxgbit/cxgbit_ddp.c
> +++ b/drivers/target/iscsi/cxgbit/cxgbit_ddp.c
> @@ -179,7 +179,7 @@ cxgbit_dump_sgl(const char *cap, struct scatterlist *sgl, int nents)
>  	for_each_sg(sgl, sg, nents, i)
>  		pr_info("\t%d/%u, 0x%p: len %u, off %u, pg 0x%p, dma 0x%llx, %u\n",
>  			i, nents, sg, sg->length, sg->offset, sg_page(sg),
> -			sg_dma_address(sg), sg_dma_len(sg));
> +			(u64)sg_dma_address(sg), sg_dma_len(sg));
>  }
>  
>  static int cxgbit_ddp_sgl_check(struct scatterlist *sgl, int nents)

You could create a temporary:

 	for_each_sg(sgl, sg, nents, i) {
		dma_addr_t addr = sg_dma_address(sg);

		pr_info("\t%d/%u, 0x%p: len %u, off %u, pg 0x%p, dma %pad, %u\n",
			i, nents, sg, sg->length, sg->offset, sg_page(sg),
			&addr, sg_dma_len(sg));
	}

>